Converter? For those with a 383 stroker and TH350 combo

[NorthernILtbucket]

When it comes to figuring out what stall converter is best I am at a total loss. I have the 383/TH350 combination with moderate rear end gearing using stock Lincoln Versailles gearing. It wants to stall at the stop light and idles nicely at about 1000 rpm in neutral. Air fuel mixture is set for best vacuum while in gear on the two 450 holley's. Timing is advanced about 12 deg. It currently cruises nicely at most speeds. Sputters just a bit at initial acceleration. As far as I can tell it now has the stock converter.
Does a 3000-3500 stall sound reasonable when I go to replace? It seems to be somewhat common for the T,s with this engine trans combo. The whole total weight thing seems to be throwing people I ask for suggestions. Thought I would ask the guys who have the light weight cars and have dealt with this before as internet searches return many different suggestions.

 

[Island Girl]

When it comes to figuring out what stall converter is best I am at a total loss. I have the 383/TH350 combination with moderate rear end gearing using stock Lincoln Versailles gearing. It wants to stall at the stop light and idles nicely at about 1000 rpm in neutral. Air fuel mixture is set for best vacuum while in gear on the two 450 holley's. Timing is advanced about 12 deg. It currently cruises nicely at most speeds. Sputters just a bit at initial acceleration. As far as I can tell it now has the stock converter.
Does a 3000-3500 stall sound reasonable when I go to replace? It seems to be somewhat common for the T,s with this engine trans combo. The whole total weight thing seems to be throwing people I ask for suggestions. Thought I would ask the guys who have the light weight cars and have dealt with this before as internet searches return many different suggestions.

I'm new here and building my first T myself, so I had that same question . . .

I was able to find 2 quite lengthy threads on the "What's the best converter stall speed" topic, and to sort of summarize, ...

If you have a healthy motor, and need it to have good manners when you want it to stay stopped at a stop-light without needing two men and a large boy to hold the break pedal, then look for something in the 2600 to 3200 range.

If you have power brakes, you can usually get away at the lower range more easily.

Two 450 holleys sounds suspiciously like a tunnel ram setup, so I'd expect some cam and compression to go with it.

If that's the case, then I'd add some gear and a 2800 to 3200 converter at minimum. You'll need to RPM quickly if you want the tunnel ram to get into its power band before it pukes.

That combo is going to like right about 36* total timing


Darlene

 

[2old2fast]

W/O cam , compression ,rear gear ratio (at least) any converter OR timing recommendation is futile....even knowing those things it's still a guess at best , that's why you're getting different info from different sources....

 

[Island Girl]

W/O cam , compression ,rear gear ratio (at least) any converter OR timing recommendation is futile....even knowing those things it's still a guess at best , that's why you're getting different info from different sources....

I think he's indirectly told us a lot of that info, or at least gave it close enough for a general recommendation . . .

Stock Versailles gearing would put it close to the 3.23 end of the range, It's a 383, no one reasonably builds a 383 without a decent cam and nominally 9.5 to 10 to 1. . . I know that's an assumption, but it is a fair one

I'd really like to know what it has for heads, old cast iron, newer vortec, or after market aluminum . . air-flow capability means a lot

The base timing doesn't mean much without knowing what kind of curve is in the distributor, but I've yet to see a chevy build that didn't like 34 to 36 total timing as a good point to test around.

Dual quads with high way gears, especially if it's a tunnel ram is going to need some serious stall

 

[Pushrod]

We could discuss this topic all day, so I went to a torque converter manufacturer in my area. I'm going with a basically stock wimpy '75 Corvette 350 and a Turbo 400 tranny...they told me a stock converter (1200-1500) would be the best for the weight of the vehicle. He went on to say that GM put small diameter low stall converters into their lighter cars for a reason. There are many variables to consider like cam, gear ratios, etc., but vehicle weight seems the simplest way to make a choice. (just my 2 cents)

 

[2old2fast]

That's way too much guessing and suggesting from ASSumptions for me to lay out my money , courseif you can afford to just keep buying converters till you get the right one ??

 

[Gerry]

I had mine stalled by 500 rpm over standard. Also did this for a customer (plus brazed fins) who had fought the stop light creep for years. He was over the moon when he got the car back as its just stayed still with light force on the brake.

Be careful over the power brake thing. The stall should suit the car, power brakes or not. Remember TC 's make heat and lots of it. JW Racing told me that just 10 seconds held on stall a TC will produce enough heat to take a bucket of water from ambient to boiling.

If you use the advantage of power brakes to hold the car, the TC will be producing more heat than if its stalled correctly. Excessive heat is the TC's/transmissions enemy.

most "good" transmission shop can get your TC stalled for you, rather than buying a new one. Been looking for a TC for my Topolino altered... a good one stalled to 3200 comes in around $350-395.

my 2c.

 

[Island Girl]

I had mine stalled by 500 rpm over standard. Also did this for a customer (plus brazed fins) who had fought the stop light creep for years. He was over the moon when he got the car back as its just stayed still with light force on the brake.

Be careful over the power brake thing. The stall should suit the car, power brakes or not. Remember TC 's make heat and lots of it. JW Racing told me that just 10 seconds held on stall a TC will produce enough heat to take a bucket of water from ambient to boiling.

If you use the advantage of power brakes to hold the car, the TC will be producing more heat than if its stalled correctly. Excessive heat is the TC's/transmissions enemy.

most "good" transmission shop can get your TC stalled for you, rather than buying a new one. Been looking for a TC for my Topolino altered... a good one stalled to 3200 comes in around $350-395.my 2c.

I wasn't suggesting to use power brakes to compensate for an improperly stalled setup, only that they tend to mask the problem because they can manage the dreaded "stop light creep", and if you have them, and creep is controlled, thinking about a higher stall converter usually doesn't come to mind.

That's way too much guessing and suggesting from ASSumptions for me to lay out my money , courseif you can afford to just keep buying converters till you get the right one ??

Hopefully, the OP will reply and fill in the details . . .

Then we can see if my assumptions were reasoned from reading between the lines, or I just pulled them out of my ASSumption.

 

[Spanky]

Just my 2 cents . . . I have an aftermarket convertor advertised at 1900-2100 RPM behind the TH 350 in my T, which probably performs like a stock convertor in a heavier car. These T-buckets are so light they need a little looseness in the convertor to avoid the stoplight creep. But unless you are going to race it, I don't think you need the 3,000 - 3,500 stall speed convertor, and they do generate a lot of transmission killing heat. JMHO.

 

[railroad]

If your tune is finalized at 1000 rpm idle, get a 3000-3200 and a top of the line trans cooler.

 

[Gerry]

If your tune is finalized at 1000 rpm idle, get a 3000-3200 and a top of the line trans cooler.

Wow, that's the stall (3200, cam comes in at that rpm)I have on my altered with a powerglide, trans brake and mild cam.

Worth remembering that excess stall will cost you dearly in MPG.

Trans cooler is always worth it, although I am not running one.

 

[railroad]

Not sure I understand your statement. 3200 is the stall you have in your trans?
The advertised stall is not the rpm the vehicle will begin to move. With the lt wt of the T and idling at 1000, the advertised stall will be correct for the application IMO. I would venture a guess the T will pull away somewhere around 2000 rpm.
A good visual is a stream of water against a fan blade. If the fan blade is very light it will instantly begin to turn and easily respond to any change in the stream of water. If the fan is heavy it will take a heavy and constant stream to make it move and maintain the movement.
I am building a Factory 5 roadster. The wt of these vehicles run between 22 and 2400 lbs. Using a FI crate engine that idles at 750 rpm, the manufacturer advises a 3000 rpm stall tq conv. I eventually went with a manual trans, but got the message, or warning.
If I was going to be conservative, I might consider 2800.
Something else I have found, is the advertised stall is a very broad window. I have bought 2500 rpm stall tq converters and could hardly tell the diff from the stock.
A good builder will ask the wt of the car, gear ratio and engine particulars, etc.
Sure hope the OP gets something that fits his needs.

 

[Swampdog]

omething else I have found, is the advertised stall is a very broad window. I have bought 2500 rpm stall tq converters and could hardly tell the diff from the stock.

+1 on that.

 

[Gerry]

Thats the difference between stall and flash stall. Depending on who you use to build a TC will determine how close the stall and flash stall are to your target.
Dont think I said I had a 3200 stall in my trans, just that the converter stall on my altered using a Powerglide etc etc.

 

[Neshkoro]

Stick shift with a clutch solves all those problems.
Just sayin'

 

[Neshkoro]

The more I read about stall speed, the more confused I get.

 

[2old2fast]

Stick shift with a clutch solves all those problems.
Just sayin'

AMEN !!!!

 

[Gerry]

Its easy really. Have your TC stalled by around 500 rpm and you should be good to go in most T's, unless they are running a 'nervous' engine.

I can still remember over 40 years ago cutting TCs open, turning down the turbine, tweaking the fins and welding them back together. First try we managed to get the stall speed to just over 4000 rpm. Cut it apart again and installing a new turbine with less turned off it got the stall to a more sensible 2800.

OK heres a simple explanation. I hope...

Stall: Foot on the brake, throttle until the engine will not go any further on the RPM. That's stall and should be done only if really necessary. If the rpm goes to, say 1800 thats the stall speed.

Flash stall. From a stand still its the rpm the engine will go (and stall out) to as the car moves. This is always less than the brake stall above.

Trans brake. Selects reverse and 1st (sometimes second) at the same time, which effectively locks the trans solid. This is a way to get a car to stall out at the max in the same way as holding it on the brake and hitting the throttle. When you want to go you release the trans bake button which 'unlocks' reverse and as the trans has first gear already selected, immediately gives you drive at the stall speed. My altered has the stall set for the cam shaft profile so it is already in the 'power band' when I launch.

Where is Screaming metal? he would be on this subject like a rash....

 

[NorthernILtbucket]

I bought the car used with motor already built so details are sketchy. I do have an aluminum high rise and old aluminum comp heads. They are from the old competition head company stamped with #347. I hear all their old records are gone so not a lot of details available. I have a trans cooler underneath with its own electric fan. I need to check gear ratio but it does feel like stock 3:23 or close to it. I would assume the engine is mildly built as it was an old short track engine to start with. It doesn't seem to have to wild of a cam as it idles pretty smooth even at lower RPM's. Manual disc brakes all around. The distributor is an old Pertronix Flame Thrower with the vacum advance locked down.

I need a place to start and as like you state there are too many variables I do not know without borrowing or buying equipment to figure it out or taking it apart. I am also not necessarily after peak performance but just a reasonable driver which it is but I hate using neutral at stop lights. It does hit pretty hard when putting it back into gear. Like others, the more I read the more confused I get.

 

[Indycars]

I do have an aluminum high rise and old aluminum comp heads.

Are they on the engine or on the shelf, cannot tell from your comment for sure?

I need to check gear ratio but it does feel like stock 3:23 or close to it.

Do you know how to check by rolling the rear tire one revolution and counting the driveshaft
revs? If it's a limited slip diff, that will make a difference in how you count.

It doesn't seem to have to wild of a cam as it idles pretty smooth even at lower RPM's.

Ok, then why are you idling at a 1000 rpm, should be around 600 to 750 rpm? I'm confused!

Why not call 3-4 TC companies and see what they say. Don't tell them anything about what
the others have recommended. Take an average of those 3-4 companies. Check out their
websites and see what questions they are going to ask. They usually have a form you can
fill out.